(1) Field of the Invention
The present invention is directed to strain sensors. In particular, the present invention is directed to a uniform lead zirconate titanate sensor that locates and quantifies the strain energy from a structure.
(2) Description of the Prior Art
Currently, technology is being pursued that will aid the development of artificially intelligent structures or devices. These structures or devices that are considered intelligent are capable of detecting and recording parameters associated with their environment by assessing physical properties such as temperature, pressure, humidity, seismic and mechanical vibration, and optical imaging. Once the physical parameters are detected, a given algorithm within the sensor interprets the measured parameters of the surroundings and the structure or device responds to the stimulus as programmed.
One application for the use of artificially intelligent structures is to develop boat and ship hulls with such capabilities. For example, hull array technology is the concept of producing submarines with hulls containing integrated sensors that can passively investigate the submarine's surroundings. The integrated hull array sensors detect acoustic energy found within a body of water in which the submarine is traveling. The received signals can alert the submarine to impending dangers such as torpedoes, land mines, or other submarines. Non-threatening acoustic emissions are also present in an open-sea environment generated by marine life. The interpretation of the measured signals by the sensors allows the vessel to listen to its surroundings in multiple directions and distinguish between various acoustic emissions.
To accomplish integrated hull array technology, what is needed is a uniform lead zirconate titanate sensor that locates and quantifies the strain energy from a structure, and is capable of being embedded into a composite material. A standard lead zirconate titanate sensor has a directional dependence on the strain measurement as a result of the rectangular shape of the lead zirconate titanate wafer portion of the sensor. What is needed is a uniform lead zirconate titanate sensor that is not directionally dependent, because the lead zirconate titanate wafer has a constant radius. The constant radius creates a uniform strain despite the direction of the wave front contact point on the lead zirconate titanate sensor. Therefore a uniform lead zirconate titanate wafer unlike a rectangular one registers the same voltage reading regardless of the path of the strain wave.